Skidder boom for tractor vehicles

ABSTRACT

An articulated skidder boom includes a main boom pivoted to the rear of a skidder vehicle frame and a jib boom pivoted to the main boom. A winch mounted near the base of the boom has a winch cable which extends along the main boom to a guide sheave at the intersection of the main and jib booms and then through a fairlead at the outer end of the jib boom. Boom-operating cylinders enable swinging movement of the fairlead through a substantial arc from adjacent ground level to a position well above the vehicle and to various distances from the winch. A boom support bracket at the rear of the vehicle supports the outer end of the jib boom in one of three vertical positions to stabilize and resist rearward movement of the jib boom when the winch cable is under load. The winch and boom combination can be used for both log-skidding and log-loading operations, with the fairlead positioned accordingly.

United States Patent [1 1 Batson Oct. 9, 1973 SKIDDER BOOM FOR TRACTOR VEHICLES Primary Examiner-Albert J. Makay [75 1 Inventor: Dossie M. Batson, Portland, Greg Attorney stephen Blow et [73] Assignee: Logging SystemsJne, Portland, [57] ABSTRACT Oreg- An articulated skidd'er boom includes a main boom 22 t V pivoted to the rear of a skidder vehicle frame and a jib I July 1971 boom pivoted to the main boom. A winch mounted [21] Appl. No.: 165,969 near the base of the boom has a winch cable which extends along the main boom to a guide sheave at the 5 H intersection of the main and jib booms and then 2] U 8 Cl 212/7 214/130 through a fairlead at the outer end of the jib boom. Boom-operating cylinders enable swinging movement [51] Int. Cl. B66c 23/06 fth f dth h bt {I f V t 581 Field of Search 214/s5.5, 523, 77 R, P '"*I 21 4 I130 21259 7 ground level to a position well above the vehicle and to various distances from the winch. A boom support bracket at the rear of the vehicle supports the outer [56] References Cited end of the jib boom in one of three vertical positions UNITED STATES PATENTS to stabilize and resist rearward movement of the jib 2,691,451 10/1954 Westfall 214/523 X boom when the winch cable is under load. The winch 5 and boom combination can be used for both log- 61g 3,601,169 8/1971 Hamilton 212/59 R-X z z g f g igg gjggf operanons wlth the falrlead FOREIGN PATENTS OR APPLICATIONS 11 Claims 5 Drawing Figures 1 9 639,558, 11/1963 Belgium 212/59 R r 308,381 10/1969 Sweden 212/59 R I 68 ya HH 66 58 35 3 I \I 3e PATENTEDUET 9M 3'.7s4,020

SHEET 10F 2 DOSSIE M. BATSON INVENTOR BY BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS PATENTEDBET elm 3,764,020

SHEET 2 OF 2 35 3 DOSSIE M. BATSON 3 9 INVENTOR BY BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS SKIDDER BOOM FOR TRACTOR VEHICLES BACKGROUND OF THE INVENTION I i l. Field of the Invention The present invention relates to log skidder vehicles and more particularly to a skidder boom and winch combination adapted for mounting on a skidder vehicle.

2. Description of the Prior Art Conventional winch and boom type log skidders of the prior art mount a single short mast rigidly to the rear of the skidder vehicle behind a winch. A fairlead on the outer end of the mast is at a fixed elevation and at a fixed distance from the winch drum. Such rigid masted skidders are one-purpose vehicles in that they cannot be used for log-loading operations.

Furthermore, because of the fixed position of the mast, and thus the fairlead, such skidders are not well adapted for skidding logs up or down steep hillsides, when it is desirable to vary the amount of lift applied to the logs.

Also, there is usually about a 2-foot distance between the fairlead and the winch drum of a conventional skidder. Therefore the winch winds the metal butt rigging of the load cable onto the winch drum when the logs are skidded in close to the mast. When this happens, the butt rigging can cut the winch cable, weakening it or causing a break, which can be highly dangerous. Also the cable is expensive to replace.

Another disadvantage of the conventional skidder is that the fairlead on its fixed mast is positioned at a considerable non-adjustable distance above ground level, threby providingsome lift to the logs as they are skidded, at least when they are fairly close to the skidder vehicle. However, an elevated fairlead is not desirable when skidding logs downhill where there is a danger of the logs running freely toward the vehicle.

An elevated fairlead is also undesirable in handling heavy loads which tend to tip the vehicle through the leverage appliedby the load to the mast.

Thus there is a need for more versatile type of skidder boom apparatus that would eliminate, or at least minimize, the foregoing disadvantages of the conventional winch and mast-type skidder.

SUMMARY OF THE INVENTION In accordance with the present invention a skidder vehicle is equipped with the usual winch, and also an articulated power-operated skidder boom with a fairlead mounted at the outer end of a jib boom section. The main and jib boom sections can be manipulated to vary the vertical position of the fairlead with respect to ground level and the winch, and also to vary the distance between the winch and the fairlead to accomodate skidding in various types of terrain, including up or down steep hillsides. The jib has sufficient reach to enable use of the boom structure for log-loading operations in preload devices such as the log-loading bunks shown in applicants prior U.S. Pat. No. 3,549,027, issued Dec. 22, 1970.

A' jib boom support bracket mounted at the rear of the vehicle supports the outer end of the jib boom in various vertical positions of adjustment during a skidding operation in a manner to resist rearward movement of the boom when the winch cable is under load.

According to another feature of the invention, the winch cable extends from the winch drum along both lar construction to support the butt rigging within the jib boom should it be reeled in through the fairlead.

Primary objects of the invention, therefore, are to provide a low-cost, easily operated, articulated skidder boom and winch apparatus for log-skidding vehicles capable of moving the fairlead into a wide range of positions with respect to the winch drum to enable skidding in extreme types of terrain as well as more normal terrain and to enable use of the skidder boom for logloading operations.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other objects, features and advantages of the present invention will become more appar' ent from the following detailed description, which pro ceeds with reference to the accompanying drawings wherein: I 7

FIG. 1 is aside elevational view of a tractor vehicle mounting a skidder boom apparatus in accordance with the invention;

FIG. 2 is a sectional view on an enlarged scale taken along the line 2-2 of FIG. 1;

FIG. 3 is a view of the outer-end of the jib boom viewed on an enlarged scale along the line 33 of FIG. 1; and I FIGS. 4 and 5 are side elevational views illustrating the operation of the apparatus in various positions of adjustment.

. DETAILED DESCRIPTION With reference tothe drawings, FIG. 1 shows a logskidding apparatus 10 of the invention mounted on a wheeled tractor vehicle 12 known in the art as a log skidder designed for skidding or towing felled logs from the woods to a landing or loading point using a winch cable with butt rigging near its outer end for attaching choker cables thereto. Such rigging and chokers are well known in the art. The chokers are adapted to en circle one or more logs and grip them tightly when tension is applied to the winch cable. Commonly such skidders include a frame 14 which may be either articulated as at 16 as shown, or rigid, and which includes a forward frame portion 18 supporting an engine 20and a dozer blade 22 at the forward end of the vehicle. An operators cab 24 is mounted on theframe rearwardly of the engine, and a rear frame portion 26 extends behind the cab and mounts the log-handling apparatus. Such skidders may be either wheeled as shown or crawler-type vehicles.

In accordance with the present invention, the usual rigid boom stick or prior skidders is replaced by an articulatedboom structure 28. This structure includes a main boom 30 pivoted at 31 to rear frame portion 26 for movement in a vertical plane and a jib boom 32pivoted at 33 to an outer end portion of the main boom for articulation in the same plane as the main boom. An angular outer end portion 35 of the jib boom projects rearwardly from the remainder thereof when such outer end portion is positioned generally at a level between the upper and lower limits of the vehicle frame as shown.

This outer end portion 35 of the jib mounts a socalled four-square fairlead 38. This fairlead is shown in greater detail in FIG. 3 and typically includes a pair of laterally spaced upright rollers 39, 40 and a pair of vertically spaced horizontally extending rollers 41, 42, all arranged to form a square opening therebetween through which a winch cable 43 extends. The roller arrangement enables the winch cable to extend through the fairlead in any direction to a load of logs, either in a straight lead through the fairlead or in an angular lead upwardly, downwardly or laterally to either side thereof. This four-square type of fairlead is well known in the art and is advantageous because it enables hauling in a winch line under load from any angular direction from the outer end of the jib boom within wide limits.

Main boom 30 actually comprises two laterally spaced sections 30a, 30b (see FIG. 2) so that the main boom can straddle a power-operated winch 46 mounted on rear frame portion 26. Such winch includes a winch drum 47 on which load cable 43 is stored.

From winch drum 47 load cable 43 extends along mainboom 30 to a guide sheave 48 at the pivotal intersection 33 of the main boom and jib boom. This intersection is shown most clearly in FIG. 2. A second guide sheave 58 is positioned at an elbow 59 formed at the intersection of the outer end portion 35 and the main portion of the jib boom for guiding the winch cable from sheave 48 along jib boom 32 and through fairlead 38. The positioning of guide sheave 58 with respect to the fairlead and jib boom is shown most clearly in FIG. 3.

The means for articulating the main boom includes a first fluid-powered cylinder 50 pivoted at 51 to a rear end portion of the winch casing and at 52 to an outer portion of the main boom. The means for articulating the jib boom relative to the main boom includes a second fluid-powered cylinder 54 pivoted at 55 to the main boom and at 56 to an inner end of the jib boom. The arrangement of articulating cylinders shown enables movement of the outer end of the jib boom and its fairlead through a wide arc, from a lower limit position shown in FIG. with the fair-lead adjacent ground level rearwardly of the skidder to an upper limit position even beyond that shown in FIG. 4 wherein the fairlead is at a level considerably above the skidder cab for loading operations or for exerting maximum lift to logs being skidded.

From FIGS. 2 and 3, it will be apparent that the jib boom is of hollow tubular construction and of generally square cross-sectional shape. Winch cable 43 extends from sheave 48 within the jib boom and about guide sheave 58 through the fair-lead 38. The advantage of the hollow tubular construction of the jib boom is that it enables the butt rigging near the outer end of the winch cable to be hauled in through the four-square fairlead and into the jib boom without falling of its own weight through the jib to foul the apparatus.

From FIGS. 1, 4 and 5, illustrating the articulated boom in various positions of adjustment, it will also be apparent that the effective lengths of the main boom and jib boom correspond roughly to the length of winch cable extending along each boom section, regardless of the positions of adjustment of the booms. The effective length for the main boom is considered to be the straight line distance between its pivot 31 and its pivot 33 whereas the effective length of the jib boom is considered to be the straight line distance between its pivot 33 and its fair-lead 38. This relationship of the booms and load cable enables articulation of the booms to any desired position without the operator having to bother to reel in or pay out cable to accomodate suchvarying boom positions and without producing any appreciable slack in those portions of the cable extending between the winch and the outer end of the jib boom. This relieves the operator of having to worry about producing undue cable slack while manipulating the booms, which slack might otherwise foul the apparatus or overstress the cable, booms or other components should the cable be under load.

Another unique feature of the load-handling apparatus is a boom support bracket structure 62 extending upwardly from the rear end of the vehicle frame. This structure provides multiple, in this case three, support positions for the outer end of the jib boom. These support positions are determined by notches 62a, 62b and 62c formed in the bracket to define finger portions 63. The elbow portion 59 of the jib boom includes a trunnion 64 adapted to seat itself within any selected one of the three notches as shown in FIG. 1. With the trunnion seated in a notch, the finger portion 63 of such notch resists rearward movement of the jib boom when cable 43 is being used to skid a log, thereby preventing overstressing of any other component of the apparatus.

The jib boom 32 includes a heeling bar 66 on its underside against which the inner ends of shorter lengths of logs abut in the manner shown in FIG. 4 in the handling of such logs by the jib boom. The main boom 30 similarly has a second heeling bar 68 which can be used as shown in FIG. 4 to stabilize longer logs lengths handled by the jib boom.

OPERATION In FIG. 1 the articulated boom structure is shown in one of its three normal skidding positions in which cable 43 might be reeled in by the winch to skid logs from the woods toward the vehicle. Alternatively the vehicle could be moved in a forward direction to tow a log from the woods with the boom in such position. When in the upper notch of the support bracket, the jib boom would be in a high skidding position providing a greater lift and thereby lesser resistance of the log to skidding than would be the case should the jib boom be positioned in a lower notch. Such high lift position might be desired when skidding uphill. The lower notch positions would be used, for example, when greater resistance of the log to rolling were desired, such as when skidding logs downhill toward the machine. The intermediate notch position might be used when skidding on level ground.

As shown in FIG. 5, the fairlead of the jib boom can also be positioned in an extremely low position adjacent ground level when desired. Such low position might be desirable, for example, to keep the full length of the log on the ground to maximize resistance of the log to rolling when skidding down steep slopes or when, because of the heavy load involved, there would otherwise be danger of tipping the vehicle.

FIG. 4 shows the jib boom in a position wherein the apparatus might be used to load a log either on a vehicle or onto a preload device.

Having illustrated and described what is presently a preferred form of the invention, it should be apparent to those skilled in the art that the same permits of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the following claims.

1 claim:

1. A log-handling boom apparatus for a skidder-type tractor vehicle having a base frame mounting an operators cab and a base frame portion displaced longitudinally of said cab toward one end of said vehicle, said apparatus comprising:

power winch means carried by said base frame portion, articulated boom means, consisting of a single rigid main boom pivoted on said base frame portion for movement in a vertical plane and a single rigid jib boom pivoted to an outer portion of said main boom for movement in the plane of movement of said main boom, I

means for articulating said main and jib booms about their respective pivot axes,

fairlead means on the outer end of said jib boom, and

guide sheave means on said boom means for guiding a winch cable from said power winch means through said fairlead means,

said articulating means being operable to move said fairlead means to various working positions toward 7 said one end from said winch means, including (1) a first position well above the upper level of said cab and remote from said winch means, (2) a second position below the upper level of said cab and directly behind and close to said winch means and (3) a third position below said base frame portion near ground level just beyond said one end of said vehicle.

2. Apparatus according to claim 1 wherein said fairlead means includes roller means for handling said winch cable under load in a straight lead, in laterally opposite angular leads and in vertically upward and downward angular leads from said jib boom.

3. Apparatus according to claim 1 wherein said winch cable extends from said winch means along said main boom and jib boom to said fairlead means, with the length of said cable extending along each said boom corresponding closely to the effective lengths of said booms in all positions of said booms whereby said booms can be articulated without reeling in or paying out cable and without creating any substantial slack in the portions of said cable extending between said winch means and said fairlead means.

4. Apparatus according to claim 1 wherein said fairlead means comprises a four-square fairlead.

5. Apparatus according to claim 1 including boom support bracket means carried by said frame portion for supporting an outer end portion of said jib boom in multiple vertical positions of adjustment.

6. Apparatus according to claim 5 wherein said support bracket means includes means for resisting rearward movement of said jib boom when said winch means reels in said cable under load.

7. Apparatus according to claim 1 wherein said jib boom includes a first heeling means for engaging a log handled by said jib boom and said main boom includes a second heeling means for engaging longer log lengths handled by said jib boom.

8. Apparatus according to claim 1 including boom support bracket means positioned on said base frame portion near one end of said vehicle for supporting an outer end portion of said jib boom in a low-level position of adjustment below the outer end of said main boom. 7

9. Apparatus according to claim 8 wherein said outer end portion of said jib boom and said support bracket means include mutually cooperative support portions operable to resist movement of said jib boom beyond said one end of said vehicle.

10. Apparatus according to claim 1 wherein said articulating means includes a first fluid pressure-operated extensible cylinder interconnecting said main boom and said jib boom and sized in a manner such that the effective working angle between said main boom and jib boom, as determined by a first imaginary straight line extending from a first pivotal connection between said main boom and said base frame portion through a second pivotal connection between said main and jib booms and a second imaginary straight line from said second pivotal connection to the outer end of said jib boom at said fairlead means, can be varied in a range between 45 and and a second pressure fluid operated extensible cylinder interconnecting said base frame portion and said main boom and sized in a manner such that said main boom can be swung by said second cylinder between a generally vertical disposition as determined by said first imaginary straight line to an angular disposition toward said one end of said vehicle.

11. Apparatus according to claim 10 wherein said main boom when in a vertical disposition extends upwardly to an upper end terminating just above the upper level of said cab and the effective length of said jib boom as measured from said second pivotal connection to the outer end of said jib boom is substantially no greater than the effective length of said main boom as measured from said first to said second pivotal connectlOn. 

1. A log-handling boom apparatus for a skidder-type tractor vehicle having a base frame mounting an operator''s cab and a base frame portion displaced longitudinally of said cab toward one end of said vehicle, said apparatus comprising: power winch means carried by said base frame portion, articulated boom means, consisting of a single rigid main boom pivoted on said base frame portion for movement in a vertical plane and a single rigid jib boom pivoted to an outer portion of said main boom for movement in the plane of movement of said main boom, means for articulating said main and jib booms about their respective pivot axes, fairlead means on the outer end of said jib boom, and guide sheave means on said boom means for guiding a winch cable from said power winch means through said fairlead means, said articulating means being operable to move said fairlead means to various working positions toward said one end from said winch means, including (1) a first position well above the upper level of said cab and remote from said winch means, (2) a second position below the upper level of said cab and directly behind and close to said winch means and (3) a third position below said base frame portion near ground level just beyond said one end of said vehicle.
 2. Apparatus according to claim 1 wherein said fairlead means includes roller means for handling said winch cable under load in a straight lead, in laterally opposite angular leads and in vertically upward and downward angular leads from said jib boom.
 3. Apparatus according to claim 1 wherein said winch cable extends from said winch means along said main boom and jib boom to said fairlead means, with the length of said cable extending along each said boom corresponding closely to the effective lengths of said booms in all positions of said booms whereby said booms can be articulated without reeling in or paying out cable and without creating any substantial slack in the portions of said cable extending between said winch means and said fairlead means.
 4. Apparatus according to claim 1 wherein said fairlead means comprises a four-square fairlead.
 5. Apparatus according to claim 1 including boom support bracket means carried by said frame portion for supporting an outer end portion of said jib boom in multiple vertical positions of adjustment.
 6. Apparatus according to claim 5 wherein said support bracket means includes means for resisting rearward movement of said jib boom when said winch means reels in said cable under load.
 7. Apparatus according to claim 1 wherein said jib boom includes a first heeling means for engaging a log handled by said jib boom and said main boom includes a second heeling means for engaging longer log lengths handled by said jib boom.
 8. Apparatus according to claim 1 including boom support bracket means positioned on said base frame portion near one end of said vehicle for supporting an outer end portion of said jib boom in a low-level position of adjustment below the outer end of said main boom.
 9. Apparatus according to claim 8 wherein said outer end portion of said jib boom and said support bracket means include mutually cooperative support portions operable to resist movement of said jib boom beyond said one end of said vehicle.
 10. Apparatus according to claim 1 wherein said articulating means includes a first fluid pressure-operated extensible cylinder interconnecting said main boom and said jib boom and sized in a manner such that the effective working angle between said main boom and jib boom, as determined by a first imaginary straight line extending from a first pivotal connection between said main boom and said base frame portion through a second pivotal connection between said main and jib booms and a second imaginary straight line from said second pivotal connection to the outer end of said jib boom at said fairlead means, can be varied in a range between 45* and 130*; and a second pressure fluid-operated extensible cylinder interconnecting said base frame portion and said main boom and sized in a manner such that said main boom can be swung by said second cylinder between a generally vertical disposition as determined by said first imaginary straight line to an angular disposition toward said one end of said vehicle.
 11. Apparatus according to claim 10 wherein said main boom when in a vertical disposition extends upwardly to an upper end terminating just above the upper level of said cab and the effective length of said jib boom as measured from said second pivotal connection to the outer end of said jib boom is substantially no greater than the effective length of said main boom as measured from said first to said second pivotal connection. 